article: For many years, a small percentage of homeowners have fixed solar panels   on their rooftops. Those panels collect some of the sun's energy and either change it into electricity or use it to heat water. Until recently, the panels were too expensive for average homeowners, and their designs were not attractive. Thanks to new advances, however, solar panels for homes are becoming cheaper and less large and heavy. Now more homeowners are considering using them.
  Stores begin to sell Solar panels
  Last fall furniture retailer  IKEA began selling solar panels in its U.K. stores. IKEA has brought the DIY solar choice to the public. While shopping for furniture, shoppers could not add a box or two of solar panels to their shopping cart  . IKEA is partnering with a company. The company deals with fixing and servcing of the solar panels on the roofs. So it is easy for customers to change from old energy system to solar system. If all goes well, IKEA plans to begin selling the panels in other countries soon.
  Stylish solar panels
  SolTech, a Swedish company, offers a really great solar-power solution. Instead of flat panels, SolTech covers the panels with a special glass tile.  And the shape of the glass tile fits traditional tiled roof designs. SolTech recently offers solar systems that heat the home's air or water. And it also offers one solar system that produces electricity.
   _ 
  New technology has turned windows into solar panels. SolarWindow technology enables see-through windows to produce electricity after the glass surface is added with a special coating. Amazingly, SolarWindow can produce electricity in low-light conditons and can even turn indoor, man-made light into electricity! Since buildings are getting taller and about 60 percent of an office building's surface is covered with windows, solar window could become a very popular way for people to produce energy and save money.
  Turning your home -business-into a solar-powered one is a choice that's becoming a lot more attractive these days!
question: The reason why only a few homeowners used solar panels is that they are   _  .
options: cheap but heavy attractive but expensive light and small dear and not attractive